Fuse-holder



Sept. 2, 1969 PAGANELLI FUSE-HOLDER 2 Sheets-Sheet 1 Filed March 28. 1967 W INVENTOR W $3M,

ATTORNEY United States Patent 3,465,280 FUSE-HOLDER Mario Paganelli, Varese, Italy, assignor to Bassani, S.p.A., Milan, Italy -Filed Mar. 28, 1967, Ser. No. 626,508 Claims priority, application Italy, Apr. 12, 1966, 8,311/ 66 Int. Cl. I-I0lr 13/44, 3/00 US. Cl. 339-42 9 Claims ABSTRACT OF THE DISCLOSURE A fuse-holder wherein the fuse is located in a discardable member consists of a fuse box into which the member must be inserted to complete the circuit. Upon withdrawal of the member the current-carrying contacts in the interior of the fuse box are automatically sealed off against tampering. The circuit can be refused only by insertion of a precise duplicate member.

This invention has for its object a fuse-holder of the kind the fusible wire of which is supported by an organ to be inserted on the electric circuit by means of a socket capable to intercept the leading wires of the electric plant submitted to protection.

The plug fuse-holders to be inserted into a socket for receiving electric current are well known; there is but the question of devices for only low power of interruption enable to give according limited guaranties against the dangers deriving from the electricity in general and offering solely very small possibilities of a combination with other electric devices more or less similar for the conventional electricity distributing plants.

The fuse-holder of this invention is on the contrary a device of high capacity and in conditions to give the maximum guaranties against damages caused by the electric current, more particularly in view to avoid, in the case the plug is taken away from the electric socket, any possiblity for anybody to accede also to with the fingers or any instrument whatever to the organs, leaders and the like submitted to electric current, thus offering the maximum of security to the people having to do such kinds of installations. Thus the invention renders impossible any contact with the organs leading electric current.

This new fuse-holder further imparts large possibilities of application for the protection of many different devices, due to the act that it has been conceived in order to be applied onto supporting means in combination, for instance, with other similar electric devices serving for controlling, signalling, security, driving and checking purposes, as conventional and/ or selfacting switches, differential interrupting means and the like. The use of the fuses-holder in question in these plants responsively increases thep rotective functions of these set up devices and allow to satisfy the requirements and prescriptions considered more or less oflicially for the modern electric plants, wherefor ever higher capacity is required.

The fuse-holder according to this invention comprises a female member or electric socket made of insulating stuff, showing a front mouth piece, in the interior of which the plug, which bears the fuse, is introduced, said mouth piece being closed by means of a small plate which is pushed in closing position by a spring or another flexible organ and put into condition cannot displace by itself, but to be displaced in virtue of the provision of appropriate connecting means, said mouth like made piece showing furthermore a configuration constraining the adoption of a corresponding structure for said plug comprising a male member bearing the fuse, and an elementary piece to be introduced into said mouth piece, also made in conformity 'ice with the last and provided with electric contacts projecting from the surface and serving, at the instant of the introduction of the plug, to displace the clamping organs of the closing small plate of the socket, so as to consent in this manner to lower said small plate, and to introduce the plug, such that the contacts of the last can cooperate with the contacts of the socket, the lodgement of which is in the interior of said mouth piece of the aforementioned female member.

The inner contacts of the socket are supported by flexible means which are preferably the same that serve to impose their action onto the connecting means such that they can lean in appropriate manner on the plug contacts. In view to avoid any extemporal disconnection of the plug, its contacts are provided with shoulders conveniently connected and put beneath the contacts of the socket, while the small covering plate remains engaged by the organs susceptible to exclude the action of the flexible means tending to hoist said small plate and to expel the plug. These shoulders of the plug contacts are realised in such a manner that at the instant of the extraction of the plug, they will provoke the expansion of the organs engaged with said small plate and with the contacts of the socket, to hold the same at a certain distance till said small plate will have wholly covered the mouth piece, and further where it will now cooperate with the engaging organs which impede its lowering.

The plug presents at its rear part an internally hollow body, used as a grip for the operations of insertion and disinsertion and carry internally the fuse between the two electrically leading organs, said fuse being enclosed within an arch-extinguishing means as for instance quartz powder, what consents to make use if a fusible thread of high capacity interruption.

The socket is provided with controlling means for instance a signalisation lamp, that signalises the interruption of the circuit, that is to say that the fuse is molten. Said socket presents also some series of terminals ensuring the electric connection of the leading thread directed to the different electric circuits, wherefor the fuse-holder, object of this invention, will protect simultaneously more electric circuits.

An embodiment of this invention is shown as a not limiting example, in the attached drawings, of which:

FIGURE l shows in a perspective view, the complex fuse-holder with the plug inserted;

FIGURE 2 shows in a perspective view the same fuseholder together with the plug disconnected;

FIGURE 3 shows, in an enlarged scale and in cross cut, along a transversal plane in the portion lodging the electric contacts, the coupling between plug and socket;

FIGURE 4 shows the same cut of FIGURE 3 with the plug disconnected; and

FIGURE 5 shows an embodiment of the fuse-holder setting up in a supporting plate.

The fuse-holder, object of this invention, includes a female part, or socket l presenting a housing made of insulating material, and bearing at its front a mouth 2, and a male part, or plug 3, to the purpose of insertion into said mouth 2.

The mouth 2 (FIGURES 2 and 4) presents at its bottom a peripheral shoulder 4, restraining the passage to the sizes of the elements of the plug 3 to be inserted. The border of said shoulder is delimited so as to impart a particular configuration to the hole like made passage. For instance, within the middle portion of said hole, there are provided two opposite projecting pieces 5, which further restrain the passage in form of a hole and impose the use of a plug the configuration of which has to correspond to said particularly shaped hole, in order the same can be introduced thereinto. When theplug is disconnected, the

mouth bottom is closed by means of a plate 6 which is thrown against the closing position by a spring or a pair of springs 7 acting between a seating 8 at the bottom and a seating 9 lodged beneath said closing plate 6. In the closing position, plate 6 is prevented from being displaced out of its position shown in FIG. 4 by being engaged with two pairs of clamping members 10 and 11 provided with lower projections 10 and 11 which engage beneath corresponding shoulders 12 and 13 of said plate 6 and are held in place by virtue of the throwing action of corresponding lateral springs 14 and 15. At its upper portion said clamping members show further projections 16 and 17 of larger sizes provided at their upper portion with biased surfaces with the purpose to be explained later.

Members 10 and 11 are set up in pairs on forks 18 made of electrically conductive stuff and there are thereon fixed reciprocally opposed the electric contacts 19 and 20; a pair of said contacts is used for each fork 18. There are generally provided two of such forks 18 electrically connected with respective lateral terminals 21 (FIGURES l and 2) and two series of terminals 22 and 23, disposed side by side.

By means of such a disposition, internal contacts 19 and 20 of the socket are practically inaccessible, inasmuch as they are not allowed to displace plate 6 with the view to lower it, said access being further impeded besides of the fingers of the hand of the user, also to any and whatever instrument. Consequently there is eliminated any danger of undue access to the organs or members under electric current, when the plug is extracted from its position of exercise.

Plate 6 presents at its upper portion a longitudinal rib 24 to the purpose of coupling with a corresponding groove 25 worked on the front portion of plug 3 to the scope of positioning said plug into its correct position at the instant of insertion in view of facilitating the correct coupling between plug and mouth.

Plug 3 (FIGURES 1, 3 and 4) comprises two symmetrical shells 3 and 3" connected and fixed one another by means of a central bolt or rivet 26. These two shells are configured so as to form the more restrained portion 27 to be inserted into the socket, and a rear portion 28 of larger sizes in respect of the former one and internally hollow, wherein two electrically conducting supports 29 and 30 are lodged, between which the fusible wire 31 is stretched, said supports 29 and 30 being respectively connected with the electric contacts 32 and 33 projecting from the thin member 27.

Part 28 is provided with an external knurling surface I 34 so as to also sustain socket member in the operation: of insertion and extraction thereof.

Part 27 of the plug comprises a middle zone 35 more restricted in wideness and provided to pass between projections 5 of the mouth piece 2. Contacts 32 and 33 show a side portion comprising an arch like projection 36 connected for a sufiiciently large area in the form of an almost vertical wall 38. The position of both contacts is such that last are situated in correspondence with the position of the elements 16 and 17 of clamping organs 10 and 11.

Due to this disposition, when the plug is introduced into the mouth piece 2, there will be, before all, obtained that the coupling of rib 24 will take place with groove 25, what will ensure the exact positioning of the plug. Thus, on further throwing the plug, contacts 32 and 33 will act through the members 36 onto the biased surfaces 16 and 17, thus constraining said surfaces to expand in opposition to the action of springs 15 and 14. Shoulder 10 and 11' will also expand in turn, thus liberating the small plate 6 which in this condition will be lowered.

The element 27 of the plug comprises vertical walls 39 which impede the clamping means to near each other during the insertion, till the instant at which contacts 32 and 33 join a position wherein they cooperate with contacts 19 and 20 and till the instant at which projections 36 will have overgone the contacts 19 and 20. Biased surfaces 40 and 41 allow that the clamping organs near one another, this being the result of the action of springs 14 and 15, so that the pairs of contacts 19 and 20 will be strongly thrown against contacts 32 and 33. Said nearing of the clamping organs and contacts will also provide for the nearing of lugs 42 and 43 which will cooperate with holes bored on the sides of plate 6 thus impeding that last displaces upwards.

FIGURE 3 represents the plug at its conform position.

One of the walls of the socket, for instance wall 44, is provided with openings for the terminals, a hollow place being previewed at the side of said wall. In the internal portion, a small signalising lamp 43 is attached, conveniently supported facing a small transparent window 46 that opens at the upper wall mentioned hereinabove. This signalising lamp is of the kind comprising a strong electric resistance and is put in parallel connection by means of a fuse 31.

In this manner, when the current traverses the fuse, lamps is short-circuited and doesnt lighten. When, on the contrary, the fuse has molten or the plug has been taken away, the electric current traverses said lamp 45, which will then light, thus signalling that the fuse is burned out or that the plug has been disconnected.

The chamber containing fuse 31 is generally filled with a material susceptible of extinguishing the electric arc, which is formed because of short-circuiting and the fusion of the security fuse; this material is preferably powdered quartz. There is, in this manner, given the possibility to make use of a fusible wire of greater interrupting capacity. The upper portion of said chamber is provided with a small window 47 for its filling with quartz powder.

Socket 1 (FIGURES 1, 2 and 5) shows on two of its opposed faces, preferably at its smaller opposed faces, two heavy ribs 48 and 49 serving as fixation organs for the mounting of socket 1 onto a suporting plate 50.

Said plate is provided with a rectangular hole, in the interior of which the upper portion of socket 1 is introduced till said ribs will lie against the edges of said hole. Said plate 50 shows at the correspondence with two recessed portions 51 and 52, wherein a screw 53 is lodged with the purpose to engage a stirrup 54, disposed so that one of its borders, the border 55 for instance, exercises a throw behind said ribs 48 and 49 at the time of screwing in of screw 53, what ensures an according blocking of both plate and stirrup. There is thus provided a simple, strong and quick engagement and disengagement mode of the socket.

There is thus easily understood how a so conceived socket will sufficiently oppose the introduction of a plug which is not of the prescribed kind, both in capacity and due to its particular configuration.

Plug 3 can be replaced in case of interrupted fuse 31 easily and quickly without any necessity of disassembling. to set up a new fuse connecting both supports 29 and 30.

Of course, the invention is not limited to the mode of realisation just described hereinabove and illustrated in the attached drawings.

I claim:

1. A circuit control device comprising, in combination a hollow female member of electrically insulating material, said female member having an opening of predetermined outline and being provided with terminals for connection to a source of electrical energy; a male member comprising two shell sections together defining a first portion configurated so as to be insertable through said opening and into the interior of said female member, and a hollow second portion rigid with said first portion, said male member further comprising connecting means extending through said first portion and connecting said shell sections with one another; first contact means provided on said first portion of said male member and including a first pair of contacts located at opposite Sides of said connecting means, and circuit fuse means inaccessibly arranged with said second portion in electrically conductive connection with said first contact means; second contact means located Within said female member conductively connected with said terminals and arranged to engage said first contact means on introduction of said first portion of said male member into the interior of said female member; a closure plate located inwardly adjacent said opening of said female member and being mounted for movement inwardly away from said opening in response to insertion of sad first portion of said male member through said opening into the interior of said female member; and biased clamping means carrying said second contact means and operative for holding said closure plate in closed position overlying and closing said opening in response to withdrawal of said first portion of said male member from said opening, and for urging said second contact means into conductive engagement with said first contact means when said first portion of said male member is received in the interior of said female member.

2. A circuit control device as defined in claim 1, said first contact means further comprising a pair of electrically conductive supporting portions spacedly arranged within said second portion of said male member and supporting said circuit fuse means in electrically conductive engagement with the same and with the respective contacts of said pair of contacts.

3. A circuit control device as defined in claim 1, said second contact means including two second pairs of contacts, the contacts of each second pair being located transversely spaced from one another and so arranged as to engage a contact of said first pair from opposite sides in response to introduction of said first portion of said male member into the interior of said female member.

4. A circuit control device as defined in claim 1, said first portion of said male member having a leading face facing said opening of said female member on introduction of said male member into said female member, said leading face being provided with a groove; and wherein said closure plate is provided with a projecting rib facing said opening and being adapted to enter into said groove in response to introduction of said male member into said female member to thereby center said first portion and said closure plate with reference to one another.

5. A circuit control device as defined in claim 1; and further comprising a body of arc-extinguishing material located in said hollow second portion of said male member and surrounding said fuse means therein.

6. A circuit control device as defined in claim 1; and further comprising signal-generating means provided in said female member and arranged to become energized for generating a signal in automatic response to burning-out of said fuse means or withdrawal of said first portion from the interior of said female member, respectively.

7. circuit control device as defined in claim 1, wherem said clamping means comprises detent means arranged to clampingly engage said closeure plate when the same moves into closure position overlying and closlng said opening, and being operative for mechanically preventing displacement of said closure plate from said closure position except in response to insertion of said first portion through said opening.

8. A circuit control device as defined in claim 7, said detent means also being arranged and constructed to clampingly engage said first portion in response to insertion of the latter into the interior of said female member to a predetermined extent, to thereby prevent undesired separation of said male member from said female member.

9. A circuit control device as defined in claim 8, and further comprising cooperating cam faces provided on said first portion and said clamping means, said cam faces being operative for preventing clamping engagement of said detent means with said first portion prior to insertion of the latter to said predetermined extent.

References Cited UNITED STATES PATENTS 2,581,308 1/1952 Smith 2001 14 2,750,571 6/1956 Schmier 339-103 2,791,663 5/1957 Cabell 200--142 2,989,739 6/1961 Wilson 340-250 FOREIGN PATENTS 516,118 1/1927 France.

1,377,268 9/1'964 France.

MARVIN A. CHAMPION, Primary Examiner.

J. H. MCGLYNN, Assistant Examiner US. Cl. X.R. 

